Tests to carry out prior to new CU

[A032701]

hi
i have been asked to quote for a job where the owner is doing an extension and wants me to do all new wiring in the new part however he wants to keep the existing wiring the same.
he also wants to change over the cu to a new metal one (mk probably). What tests do people recommend i do on the existing wiring to make sure its all safe and in good condition before i take out the old cu?
thanks

 

[SparkyChick]

At the very least IR each circuit, a good sampling of Zs on each circuit and ring final continuity checks. It's also worth looking in light switches/fittings for a CPC.

Some people insist on a full EICR, but I tend to just satisfy myself there are no major issues to contend with on the day and then do a full round of testing once the board is in.

 

[westward10]

Crossed neutral conductors on the lighting circuits.

 

[A032701]

sparky chick,
when you say ir each circuit do you mean inspection report or.....
thanks

 

[westward10]

Insulation resistance (IR).

 

[SparkyChick]

Insulation resistance to the fullest extent possible... i.e. I'll do L+N to E, but if I can disconnect everything I'll do the full suite of tests.

 

[A032701]

ok thanks

 

[ruston]

As much as you can to ensure it is OK or it is your phone that will be ringing down the line.
You will get an idea once you have done a visual and the tests advised above.

 

[sparksburnout]

Crossed neutral conductors on the lighting circuits.

If you find a borrowed neutral on the lighting circuit and the guy does not want his landing wallpaper wrecking what are you going to do?

 

[happysteve]

If you find a borrowed neutral on the lighting circuit and the guy does not want his landing wallpaper wrecking what are you going to do?

Quinetic switches, receiver fed from upstairs lighting circuit.

 

[littlespark]

If you find a borrowed neutral on the lighting circuit and the guy does not want his landing wallpaper wrecking what are you going to do?

Put both circuits on the same breaker, with a note saying why.

Have a look out for DIY bodge jobs that have been done in the house previously. Metal faceplates not been earthed etc.

 

[Gavin John Hyde]

Last board I did i ended up putting both light circuits on one breaker on same rcd too. With note on certificate as customer didnt want to do remedial works.
Being there was previously no rcds then this would be seen as an improvement.
The inconvenience factor whilst important is surely less than the safety benefits.
Queried it on the annual visit and the niceic bloke said sometimes it cant be avoided and its the camp site rule, leave it same or better than you found it

 

[Pete999]

hi
i have been asked to quote for a job where the owner is doing an extension and wants me to do all new wiring in the new part however he wants to keep the existing wiring the same.
he also wants to change over the cu to a new metal one (mk probably). What tests do people recommend i do on the existing wiring to make sure its all safe and in good condition before i take out the old cu?
thanks

Might be best to read "best practice guide 1 it tells you most of what you need to know.

 

[Pete999]

Might be best to read "best practice guide 1 it tells you most of what you need to know.

electricalsafetyfirst.org.uk easy to download, sorry I can't copy mine.

 

[sparksburnout]

Might be best to read "best practice guide 1 it tells you most of what you need to know.

Or do an I&T course.

 

[sparksburnout]

Last board I did i ended up putting both light circuits on one breaker on same rcd too. With note on certificate as customer didnt want to do remedial works.
Being there was previously no rcds then this would be seen as an improvement.
The inconvenience factor whilst important is surely less than the safety benefits.
Queried it on the annual visit and the niceic bloke said sometimes it cant be avoided and its the camp site rule, leave it same or better than you found it

I think we have all done that, I certainly have. At the end of the day NO customer is going to want his decorations pulling apart when the wiring has been sitting there for 30 years with no problem.........

 

[Pete999]

hi
i have been asked to quote for a job where the owner is doing an extension and wants me to do all new wiring in the new part however he wants to keep the existing wiring the same.
he also wants to change over the cu to a new metal one (mk probably). What tests do people recommend i do on the existing wiring to make sure its all safe and in good condition before i take out the old cu?
thanks

The best practice guide, advises the installer to recommend to the client that an EICR is carried out prior to the CU change.

 

[FatAlan]

Isn’t the EICR a bit academic really as you are going to have to test the whole lot anyway to issue the EIC. Just makes sense to look for any existing problems first as already mentioned.

 

[Pete999]

Isn’t the EICR a bit academic really as you are going to have to test the whole lot anyway to issue the EIC. Just makes sense to look for any existing problems first as already mentioned.

Was only stating what the Best Practice Guide recommends Alan, you don't have to follow the guide, as it's a recommendation from Electrical Safety First.

 

[l4urence]

The rub here is that after the change it needs to all work because it did before, so it would be deemed 'your' fault. You need to be sure with testing as above that a circuit that will trip an RCD after its fitted (and doesn't yet because there isn't one) is highlighted, known about and flagged for repair. It's not always the circuits but consumer goods plugged in, the leaking washer / dishwasher / kettle. These might be defective and nobody knows yet and they'll try to blame you.